Okay, but that’s basically every debate. Hell, that’s the optimal strategy in a crowded field. Meekly sitting in the back with a pile of spreadsheets that say “I’m right” on them does nothing to galvenize public support for your policies.
Even then, Biden refusing to meet Trump on stage won’t discourage Trump from doing his whistle stop Beer Hall tour. At some point, I think liberals lose sight of how important big crowds of people cheering at your approach is in a popularity contest. When Biden shows up at an event, he’s greeted by a few dozen angry protesters, calling him Genocide Joe and waving big blown up pictures of dead Palestinian children. When Trump shows up at an event, he’s greeted by a few dozen enthusiastic supporters, calling him the New Messiah and waving big blown up pictures of drowned children in the Rio Grande with “Win One More For the Gipper” scrawled across it.
Totally different energy at these events. Totally different reception by the party’s base voters.
If Biden wants to position himself as the “Guy Who Will Protect You From Trump Who Is Worse”, he’s going to have to get out in front of an audience, side by side with Trump, and remind everyone of the distinction. Otherwise, he’s just running in a vacuum as a mediocre President during an economic upswing, and hoping people give him credit for a rising stock market without blaming him for his party’s failure to deliver on any of their major platforms in the last 40 years.